"Folded" optical phonons inGaAsGa1−xAlxAssuperlattices

Abstract

We report the first experimental study, by means of Raman scattering, of "folded" longitudinal optical (LO) phonons in $\frac{\mathrm{GaAs}}{{\mathrm{Ga}}_{1-x}{\mathrm{Al}}_x\mathrm{As}}$ superlattices. We successfully analyze their frequency shift and Raman activity in terms of a Kronig-Penney model of lattice dynamics. The LO phonons are either localized in the GaAs "well" or propagating in both layers.